1. Field of the Disclosure
The present disclosure relates to a power converter comprising smoothing condensers which are connected in parallel and have different characteristics from each other.
2. Description of the Related Art
Japanese Laid-Open Patent Publication No. 2004-254355 discloses a power converter of a DC-AC inverter, wherein smoothing condensers comprise multiple condensers, and wherein an aluminum electrolytic condenser and a snubber condenser having a film condenser or ceramic condenser are connected in parallel.
According to Publication, the physical volume of the entire smoothing condensers is set to be smaller by reducing the capacity of the aluminum electrolytic condenser, i.e., by allowing the low frequency ripple current to be absorbed by the aluminum electrolytic condenser and the high frequency ripple current to be absorbed by the film condenser or ceramic condenser.
When adopting the smoothing condensers as multiple condensers, the entire physical volume of the smoothing condensers may be set to be small. However, in case of utilizing the smoothing condensers by merely combining the two types of condensers with different characteristics, it is highly possible that a resonance will be generated due to the relationship between an electrostatic capacity and ESL (equivalent series inductance) in each condenser connected in parallel and inductance of wiring for connecting the condensers. If the resonance is generated between two condensers connected in parallel, because resonance current flows between the condensers, the resonance current due to the resonance generation would be added when performing an original smoothing operation to thereby cause an increase in the ripple current.
In this regard, when using the power converter for high power, it may be necessary to increase the ripple current so as to withstand against the increased amount of the ripple current. This causes the smoothing condenser to be oversized. Thus, miniaturization becomes difficult.